Organic Light Emitting Display (OLED) apparatuses are self-emitting apparatuses having many advantageous features including a low driving voltage, a high light emission efficiency, a short response time, high clarity and high contrast in displayed image, near-180° viewing angle, and a wide range of operational temperatures. OLED apparatuses may be divided into two categories, a passive matrix type OLED and an active matrix type OLED (AMOLED).